Attempts to provide a satisfactory device for growing plants on large scale have not been entirely successful. Many patents have issued to myself which are directed to the use of various structures to enhance the utilization of air and water with a plant support system. Although these devices are satisfactory for home and greenhouse use they have not been readily adapted to large scale use.
The attempts to utilize air have been directed primarily to various structures to increase the surface area in which the root system of the plant is disposed. Attempts to utilize water including the addition of nutrients, herbacides, fertilizers etc. have employed various metering arrangements to maintain the soil in a moistened condition.
To date it appears that none of these devices have been adapted to wide scale agricultural use. There still exists a need for a suitable system which would be effective at low cost.
My present invention is directed to establishing separate strata of soil, air and water with hydrophilic columns providing for liquid transfer from the water stratum through the air stratum and into the soil stratum.
Many patents have issued wherein the soil which supports the plant is retained in one structure while water is retained in another structure. U.S. Pat. Nos. 4,040,207 and 4,034,506 show such structures where the floor supporting the soil is in contact with water. U.S. Pat. No. 2,486,512, discloses the use of an absorbent material or a wick to transmit water to the soil. U.S. Pat. No. 2,346,029 also discloses the use of an absorbent material or a wick to transmit water to the soil.
Broadly my invention provides a device and method which uniquely enhances the relationship among soil-air-water. In my invention the concept of aeration is granted equal prominence with water to maximize plant growth.
My invention is directed to an agricultural device having a first strata of soil or plant support material, the soil supported on a permeable floor; a plurality of hydraulically conductive columns hereinafter referred to as hydraulic columns support the floor and are received on an impermeable base, water is disposed on the base and maintained at a level such that the upper surface of the water is spaced apart from the lower surface of the permeable floor to define an air stratum therebetween. The hydraulic columns transport the water from the liquid stratum through the air stratum and into the soil stratum. In this application the term soil or plant support material means any growing medium which can support the plant being grown. Because of the relatively small volume of soil required, the depths of the soil on the floor can be controlled closely and other additives can be included to accommodate the specific needs of the soil for optimum growing conditions. For example, to achieve maximum root aeration vermiculite or a similar material may be mixed in for improved air permability.
The term water as used in this application includes water with or without additives, such as nutrients, dissolved gas, disease control agents, hormones, root conditioners, etc. which influence the plant growth and which additives can be dissolved in the water, colloidally suspended, etc.
In a preferred embodiment of my invention the base includes sides which define a reservoir to hold the water. The hydraulic columns or support members are received on the base and support, at least in part, the permeable floor on which the soil is disposed.
The method of my invention includes contacting the hydraulic column with water, flowing the water through the column and into the soil and controlling the rate of flow of the water.